In recent years, in order to achieve device miniaturization, display devices in which the display unit and the input unit are integrally formed are in wide use. In particular, display devices including touch panels that can detect a contact position where a finger or an input stylus (object to be detected) has come into contact with a display surface are in wide use in mobile devices such as mobile phones, PDAs (personal digital assistants), and laptop computers.
Touch panels of various types such as the conventional so-called resistive film (pressure-sensitive) type and capacitive type are known. Among these, touch panels of the capacitive type are in wide use.
In capacitive touch panels, a position of contact is detected by detecting changes in capacitance when a finger or an input stylus comes into contact with the display surface. Thus, it is possible to detect a contact position by a simple operation.
So-called sensor electrodes, which are position detection electrodes that detect a contact position of an object are often made of ITO (indium tin oxide) or the like. However, if the touch panel is large, then there is a problem that the resistance of the sensor electrodes made of ITO becomes large, and the detection sensitivity decreases.
Patent Documents 1 and 2 disclose configurations in which, in order to reduce resistance of the sensor electrodes, the sensor electrodes are made of metal wiring lines in a grid pattern. In order for the sensor electrodes extending in the vertical direction and sensor electrodes extending in the horizontal direction, each sensor electrode is constituted of a plurality of grid electrodes, each of which is formed into a square shape.